LED white balance

Discussion in 'Photography' started by notbob, Feb 28, 2013.

  1. notbob

    notbob Guest

    I have a pre-LED era digital powershot Canon. I've been looking at
    LED lights for macro and supermacro shots, the Bescor low output line
    (LED-40). My camera has a decent selection of wht-bal, including
    fluorescent 1&2. The Bescor lights are daylight balanced at 5600K.
    Which wht-bal setting would I use? Daylight, or must one have a newer
    camera with an LED w/b setting?

    nb
     
    notbob, Feb 28, 2013
    #1
    1. Advertisements

  2. notbob

    qrk Guest

    The LED lights I have come across in theatre shooting don't fit in to
    any canned WB setting. I use custom WB. Just be sure all your lights
    are the same for your shoot or you'll be fighting with different color
    temperatures.
     
    qrk, Feb 28, 2013
    #2
    1. Advertisements

  3. notbob

    Alan Browne Guest

    White LED's are pretty broad spectrum but do have some notches and peaks.

    http://ideatoreality.files.wordpress.com/2010/04/fig-2-white-led-vs-rgb-led-spectrum.jpg

    For general use the "daylight" setting and you should be okay.

    For critical colour processes you should get the technical data on the
    LED's spectrum and do some testing first.

    I-
    With a white or neutral-grey target, the camera manual WB technique
    should suffice. (Be careful of grey's that often have tint added to them).

    II-
    In any case, if you shoot raw, you can adjust on import to your editor.
    So take a reference shot of something white and/or grey (real neutral
    grey, no tint). On raw import you can find the correct settings to
    apply to the rest of the images.

    III-
    Otherwise:

    1. Get a collection of objects with various colors, esp. those close to
    the 3 additive and 3 subtractive colours: RGB and CYM. Put them on a
    white sheet of paper.

    2. Take a flash shot with the WB set to 5500K (flash setting) and
    neutral tint. Optionally (or in lieu) the same shot with incandescent
    (3200K) and again neutral tint.

    3. Then do the same with the LED's. Start at 5500K. (Flash) and neutral
    tint.

    Compare those. I believe for most cases, the "flash" setting should be
    about right. If the camera supports temperature settings (as above)
    then adjust as needed. Tiny (green-magenta) may be adjusted as well in
    some cameras.
     
    Alan Browne, Feb 28, 2013
    #3
  4. Or they are blueish + yellowish. Depends a lot on the specific
    LED --- some are cheaper than others. Oh, and when the LED
    ages, the spectrum changes, too.
    Even better, use a colour card and a program that calculates
    the shift between what the camera recorded in that light and
    what the card colours really are, interpolates that for all
    colours and applies that shift backwards.

    That works even for shifts that aren't correctable by global
    "colour temperature" and "tint", when e.g. only parts of the
    spectrum are weak or overly strong.
    That's a indiscriminate all-round scattergun correction ...
    at least it can be used in any RAW converter.

    -Wolfgang
     
    Wolfgang Weisselberg, Mar 1, 2013
    #4
  5. notbob

    Robert Coe Guest

    : I have a pre-LED era digital powershot Canon. I've been looking at
    : LED lights for macro and supermacro shots, the Bescor low output line
    : (LED-40). My camera has a decent selection of wht-bal, including
    : fluorescent 1&2. The Bescor lights are daylight balanced at 5600K.
    : Which wht-bal setting would I use? Daylight, or must one have a newer
    : camera with an LED w/b setting?

    The Canons I've owned define "daylight" as 5200K (and "cloudy" as around
    5700), so at the daylight WB setting your pictures could come out a little
    blue. That's easily corrected if your camera has RAW mode and/or lets you set
    the WB in degrees. Otherwise, you may have to experiment and see what works
    best for you.

    Bob
     
    Robert Coe, Mar 2, 2013
    #5
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.